Facilitating catalytic activity of indium oxide in lithium-sulfur batteries by controlling oxygen vacancies

Defect engineering plays a key role in lithium-sulfur (Li-S) batteries due to the altering of electronic states caused by defects that provide a promising opportunity to realize high-efficiency surface catalysis. Oxygen vacancies (OVs), the common defects in metal oxides, are often used to immobilize and catalyze lithium polysulfides (LiPSs). However, little effort has been devoted to developing novel oxygen defects manufacturing strategies and controlling its concentration to obtain an ideal effect. Herein, defect-rich electrocatalysts composed of In₂O_3-x nanoparticles and carbon spheres (CS) for Li-S batteries are reported by hydrothermal composition. Both experiments and theoretical calculations indicate that an appropriate quantity of oxygen vacancies can enhance the chemical adsorption and catalytic ability of LiPSs. As expected, the In₂O_3-x@CS-0.6/rGO-based cell displays an outstanding rate performance of 872 mAh g⁻¹ at 3 C and a low fading rate of 0.058% each cycle after 100 cycles at 0.2 C, as well as a favorable areal capacity of 6.98 mAh cm⁻² under high sulfur mass loading of 6.81 mg cm⁻². This work furnishes a newness strategy to the rational design of oxygen vacancies of metal oxides and boosts the development of defect engineering in electrochemical applications.